Pulsed electromagnetic fields (PEMF) are low-energy, time-varying magnetic fields that are used to treat therapeutically resistant problems of the musculoskeletal system. Those problems include spinal fusion, ununited fractures, failed arthrodeses, osteonecrosis, and chronic refractory tendonitis, decubitus ulcers and ligament, tendon injuries, osteoporosis, and Charcot foot.
The specific problem to which the invention is applicable is the desirability, in certain application, of providing a PEMF transducer design that, while formable to a selected anatomical contour, is still flexibly conformable to accommodate normal patient movement. An example of an area where such conformability would be advantageous is the hip area, where there is a significant degree of anatomical variance between patients, and where a significant amount of movement occurs during normal patient activity.
For PEMF therapy, an electromagnetic transducer coil is placed over a selected area of the skeletal system such that pulsing the transducer produces an applied or driving field that penetrates to the target skeletal area. The conventional approach has been to use either a flexible or semi-rigid transducer construction.
The flexible transducer approach is disadvantageous in that the transducer cannot maintain a desired transducer configuration without some additional form of jacketing and/or strapping. Thus, while such transducers are flexibly conformable to patient movements, they cannot be formed to maintain a desired anatomical contour.
An alternative semi-rigid transducer construction is described in the related applications. Those applications teach a transducer construction in which the windings of the transducer coil are flat wound and bonded together, and then encased in a semi-rigid polyurethane elastomer shell that can be formed to a selected anatomical contour. While the degree of rigidity can be adjusted somewhat by the selection of a specific shell material, generally this type of construction does not provide sufficient flexible conformability to accommodate patient movements.
Accordingly, a need exists for a PEMF transducer construction that provides sufficient rigidity to be formable to a desired anatomical contour, but has sufficient conformability to accommodate normal patient movement.